1. Field of the Invention
The invention relates to an indexing assembly. More particularly, the invention relates to an indexing assembly used in conjunction with a machining apparatus to rotate/position a workpiece without removing the workpiece from the machining apparatus.
2. Description of the Prior Art
Downtime is the nemesis of virtually all machine shops. When machines are being adjusted, or when workpieces are being reoriented, the manufacturing process is placed on hold and productivity accordingly goes down. Many techniques, methods any apparatuses have, therefore, been developed to minimize downtime in manufacturing processes.
For example, tool changing assemblies have been developed for automatically changing working tools on a machining assembly without the need for human intervention. These tool changing assemblies have drastically reduced the downtime associated with complex manufacturing processes. In general, changing assemblies include a processing turret which supports a spindle to which a tool is selectively secured. The processing turret orients the tool for engagement with the workpiece such that the tool may act upon the workpiece in a desired manner. Additional tools are commonly stored within a tool transfer station. The tool transfer station selectively removes and replaces tools upon the spindle as the manufacturing process moves forward.
While the development of tool changing assemblies has substantially improved the efficient use of manufacturing equipment, substantial downtime remains a common problem. Further efficiency is provided by the provision of xe2x80x9ctombstonexe2x80x9d fixtures. These fixtures commonly support a plurality of workpieces upon a central support constructed for rotation about a longitudinal axis. As such, the workpieces are supported in such a manner that they may be successively positioned for processing by the machining assembly. The tombstone""s ability to successively move the workpieces for treatment by the machine tool assembly, once again limits the need for human involvement during the manufacturing process and reduces undesirably downtime.
The combination of tool changing assemblies and tombstone fixtures has not, however, fully automated the manufacturing process and substantial downtime is still associated with high volume manufacturing operations. For example, known tombstone fixtures are designed to support workpieces in a fixed manner. These tombstones require that a human operator shutdown the machining apparatus when a workpiece must be reoriented for further processing. As with most adjustments requiring the shut down of a manufacturing process, the reorientation of the workpieces held on a tombstone fixture is highly time consuming, and accordingly highly undesirable. In addition, each time a workpiece is reoriented on the tombstone fixture accuracy is compromised. Such reductions in accuracy, even when minimal, are highly undesirable.
A need, therefore, exists for an apparatus permitting the ready adjustment of workpieces supported on tombstone fixtures. The present invention provides such an apparatus.
It is, therefore, an object of the present invention to provide a workpiece support assembly including an indexing unit adapted for the automated adjustment of a workpiece being machined. The assembly includes a central support column having at least one indexing unit secured thereto. The indexing unit includes a base member integrated with the central support column, a main body to which a workpiece may be selectively secured and a locking assembly permitting the selective locking and rotation of the main body relative to the base member. The main body is mounted on the base member for selective rotation required to rotate a workpiece as mounted.
It is also an object of the present invention to provide an assembly wherein the locking assembly is resiliently biased to selectively lock the base member and the main body in desired positions.
It is another object of the present invention to provide an assembly wherein the locking assembly includes relatively moveable inner and outer gear rings which are respectively linked to the base member and main body. The inner and outer gear rings are selectively engaged to prevent relative motion therebetween and thereby prevent relative motion between the base member and the main body.
It is a further object of the present invention to provide an assembly wherein a lock gear selectively engages the inner and outer rings to prevent relative motion therebetween.
It is also another object of the present invention to provide an assembly wherein the lock gear is spring biased into engagement with the inner and outer gear rings.
It is yet a further object of the present invention to provide an assembly including a lift arm which acts upon the lock gear to selectively move the lock gear from engagement with the inner and outer gear rings.
It is still another object of the present invention to provide an assembly including a pressure plate positioned between the main body and the lock gear for applying a spring bias forcing the lock gear into engagement with the inner and outer gear rings.
It is also an object of the present invention to provide an assembly wherein the central support column includes eight indexing assemblies secured thereto.
It is a further object of the present invention to provide an assembly wherein the indexing assembly is releasably secured to the central support column.
It is another object of the present invention to provide an indexing assembly as described above.
It is yet another object of the present invention to provide a locking assembly adapted to selectively locking rotating members relative to each other. The locking assembly includes relatively moveable inner and outer gear rings respectively coupled to a base member and a main body. The inner and outer gear rings are selectively engaged by a lock gear to prevent relative motion therebetween and thereby prevent relative motion between the base member and the main body. The lock gear flexes in a controlled manner such that it engages the inner and outer rings at different times.
Other objects and advantages of the present invention will become apparent from the following detailed description when viewed in conjunction with the accompanying drawings, which set forth certain embodiments of the invention.